1. Field of the Invention
This invention relates in general to semiconductor devices and specifically to antireflective coating (ARC) for semiconductor devices.
2. Description of the Related Art
Antireflective coatings (ARC) are used in the manufacture of semiconductor devices. For example, an ARC layer may be used in a lithography process for reducing unwanted reflections from lower structures (e.g. a gate layer of a transistor) into a photo resist layer located above the ARC layer.
Silicon rich materials (e.g. silicon-rich silicon nitride) can be used as an ARC material. One problem with using a silicon rich material for an ARC layer is that the silicon may react with the underlying material (e.g. metal in a metal layer located below the ARC layer) to form an unwanted silicide layer between the ARC layer and metal layer. This unwanted silicide layer may create a problem during the etch process in that the silicide layer may act as an etch stop layer and prevent the complete etch of the gate stack.
Another problem with a silicon rich ARC layer is that the silicon of the ARC layer may “poison” the photo resist and prevent the complete removal of the photo resist material.
What is needed is an improved ARC layer for the manufacture of a semiconductor device.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted.